[PATCH] RISCV: Fix end PFN for low memory

From: Atish Patra <atish.patra@wdc.com>
To: palmer@sifive.com, linux-riscv@lists.infradead.org
Cc: hch@infradead.org, anup@brainfault.org, atish.patra@wdc.com,
	linux-kernel@vger.kernel.org, Damien.LeMoal@wdc.com,
	terpstra@sifive.com
Subject: [PATCH] RISCV: Fix end PFN for low memory
Date: Tue, 11 Sep 2018 11:30:18 -0700	[thread overview]
Message-ID: <1536690618-9157-1-git-send-email-atish.patra@wdc.com> (raw)

Use memblock_end_of_DRAM which provides correct last low memory
PFN. Without that, DMA32 region becomes empty resulting in zero
pages being allocated for DMA32.

This patch is based on earlier patch from palmer which never
merged into 4.19. I just edited the commit text to make more
sense.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/kernel/setup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index db20dc63..a192bf8a 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -193,7 +193,7 @@ static void __init setup_bootmem(void)
 	BUG_ON(mem_size == 0);
 
 	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = pfn_base + PFN_DOWN(mem_size);
+	max_low_pfn = memblock_end_of_DRAM();
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	setup_initrd();
-- 
2.7.4

